Every horse whose sire and maternal grandsire have had a meaningful sample of offspring is assigned two Tomlinson Ratings one that assesses his likely aptitude for grass and one for muddy or sloppy dirt tracks. These ratings, updated twice each year, are, derived from tens of thousands of race results. The ratings, which appear next to the "Turf" and "Wet" headings in, each horse's career box, can range from 0 (totally unsuccessful) to 480 (spectacularly successful.) A dash (-) means that the horse's sire has had an insufficient number of runners to create a rating. An asterisk (*) means that the sire has had a limited number, or fewer than 80 starters, on a particular surface.

Tomlinson Ratings, in career box

MUDDERS AND TURFERS

Mud Rating of 320+
Merits further consideration as a horse that could run particularly well over a wet track.
Turf Rating of 280+
Merits further consideration as a horse that could run particularly well over the grass.
Tomlinson Ratings are most useful when a horse has no or few starts on grass or wet dirt and become less useful once a "horse has clearly established his ability on these surfaces.
They also may suggest whether a horse beginning his career on the dirt should be given less consideration now than when he tries the grass in a subsequent start